Donald Trump has violated almost every rule of political and social decorum in recent months. His inflammatory rhetoric now resonates across the world, finding echoes among Hindu supremacists in India and far-right politicians in Europe. Trump and his vociferous supporters seem to be setting up rancorous conflicts within and between societies.

In the process, however, Trump has made a little acknowledged, and even vigorously denied, phenomenon seem incontrovertible: Islamophobia, the prejudice that blames an ancient religion for the crimes of some present-day murderers and fanatics, and makes a diverse population of 1.5 billion people look suspect in the eyes of the rest.

This bigotry has flourished, largely unchecked, for some years now. It raised its grisly head in even proudly liberal New York during the controversy over the "Ground Zero Mosque" before running into some principled political opposition. The occasional resistance to it in the mainstream media — such as Ben Affleck's exasperated response to Bill Maher, or Reza Aslan's brisk education of a befuddled Fox News presenter — goes viral simply because it is so rare.

In a bizarre twist, the very people who promote, unwittingly or not, Islamophobia — such as Ayaan Hirsi Ali, who condemns Islam as a "nihilistic, destructive death cult" — also vehemently deny its existence. They claim that they're being attacked unfairly for wanting to reform Islam, which is evidently incompatible with Western values of democracy and human rights.

But a fundamental incoherence marks the rhetoric of those auditioning for the role of Islam's Martin Luther. They never quite clarify what it means to "reform" a religion as variously and extensively practiced as Islam. They assume that Islam is a cult of doctrine-bound believers, like Communism; and, like the Leninists of the past, they hope that ruthless assertion of the correct party line, preferably laid down by them, will discipline all 1.5 billion adherents.

The Islamophobes also mash together complex political issues — Saudi-sponsored Wahhabism in Java, failures of Indian secularism in Kashmir, racial discrimination in Republican France — into a simple rhetorical question: Is inherently violent and intolerant Islam compatible with the modern world?

This quasi-accusation assumes that the modern world, whose record includes savage wars between secular imperialist powers and atheistic totalitarianisms, as well as genocides and devastating economic crises, was doing just great until it collided with a 7th century faith. The Islamophobes also conflate terrorism, a tactic used by people of all faiths and ideologies since it was patented by the Russian revolutionaries of the 19th century, with Islam. They point, as evidence, to murderous groups like al-Qaida and Islamic State, which invoke Islam as their motivating force.

But this attempt to identify Islam's allegedly vicious core, by taking the proclamations of fanatics at face value, merely begs some more questions. Much blood has been shed in the name of liberty, equality and fraternity since the Jacobins instituted the reign of terror. People invoking democracy and human rights as their motivating force have most recently caused havoc in the Middle East. Does that make those of us who believe in democracy the pathetic dupes of an inherently murderous faith?

But then the mills of Islamophobia do not need any intellectual precision or historical clarity. What keeps them churning is the paranoia of the rich as well as the unfocused fury and rampant frustration of citizens who feel left or pushed behind in highly unequal societies.

Many people live with dread in a world where all social, political and economic forces determining their lives seem opaque. They are prone to inventing "enemies" — socialists, liberals, an alien in the White House, Muslims — and then blaming them for their plight.

We should have been alerted to this phenomenon by the entwined history of anti-Semitism and demagoguery in the modern world. It starts with Voltaire's furious denunciations of "barbarous" Jews and Judaism, and it enters its most depraved phase in the late 19th century when Jew-hatred became routine amid the political and economic traumas of middle and lower-middle classes in France and Germany.

Like anti-Semitism, Islamophobia breeds in the swamp of fear and insecurity that is truly the modern world for many people. In the hands of skillful and resourceful manipulators, it can turn into a very dangerous force, as we have now witnessed with Trump.

Trump's malign and uncontrollable absurdities make it clear yet again that there is no logic, no link between cause and effect, in the xenophobic worldview. They may continue to damage political cultures for a few more months while Muslims in the West, and many others who just happen to "look" and "sound" Muslim, wince, cower and hide.

But he and his large band of zealots have also established Islamophobia as an undeniable fact — indeed, as the most insidious and volatile mass prejudice of our time. For this vital illumination, if nothing else, we should thank God, or Allah, for Donald Trump.

Bloomberg

Pankaj Mishra is the author of "From the Ruins of Empire: The Intellectuals Who Remade Asia."